Furthermore, from DE-C2-35 37 656 is known a process for obtaining isosilybin-free silibinin, as well as medicaments containing this.
It is known that flavanolignans are, as a rule, insoluble or not very soluble in water. Because of this dissolving behaviour, the rate of liberation of these compounds and thus also the bioavailability thereof and the resorbability thereof in the body of humans and mammals treated therewith is unsatisfactory. Therefore, in the past, the attempt has been made, in the case of the flavanolignans, to bring about a molecular change by treatment or reaction with appropriate chemical agents and thus to convert them into derivatives with improved water-solubility and increased rate of liberation. The derivatives formed in this manner include, for example, adducts with, inter alia, cyclodextrin, for example silibinin-.beta.-CD (CD=cyclodextrin); complex compounds with, for example, phosphatidylcholine or with certain aminosugars; esters, especially with dicarboxylic acids, as well as inclusion compounds. It is a disadvantage in the case of these derivatives that, in individual cases, the flavanolignan in question is bound to a chemical compound which can act physiologically as a foreign substance and possibly bring about undesired side reactions or impair the effectiveness of the flavanolignan. In the case of the production of adducts, complexes of derivatives, the .gamma.-pyrone ring of the flavanone part is often opened, for example in an alkaline medium. Furthermore, in the case of the mentioned derivatives, the danger also exists that, in the case of the administration of a flavanolignan modified or derivatized in the mentioned way, this is admittedly better resorbed but brings about an action which is substantially different from that expected and desired for the flavanolignan.
It is an object of the present invention to provide flavanolignan preparations which do not have a binding of the flavanolignans to foreign compounds and possess a good, high rate of liberation by means of which a sufficient bioavailability and a good resorption by the body of the treated individual is ensured after administration thereof. These flavanolignan preparations are to have the desired and expected actions of the flavanolignans in question and to display none of the side effects or changes of their specific effectiveness or of their activity spectrum to be attributed to the binding to foreign compounds, i.e. the agents used in the above-described derivatization.